THERMOSTABLE BETA-GLYCOSIDASE FROM SULFOLOBUS-SOLFATARICUS

The Sulfolobus solfataricus beta-glycosidase (S beta gly) is a thermostable and thermophilic glycosyl-hydrolase with broad substrate specificity. The enzyme hydrolizes beta-D-gluco-, fuco-, and galactosides, and a large number of beta-linked glycoside dimers and oligomers, linked beta 1-3, beta 1-4, and beta 1-6, It is able to hydrolize oligosaccharides with up to 5 glucose residues. Furthermore, it is also able to promote transglycosylation reactions. The corresponding gene has been cloned and overexpressed both in yeast and Escherichia coli. Based on sequence acid functional data, the S beta gly has been assigned to the so-called EGA family of glycosyl-hydrolases, including beta-glycosidases, beta-galactosidases and phosho-beta-galactosidases from mesophilic and thermophilic organisms of the three domains. The S beta gly has been crystallized and the resolution of its structure is in progress. Because of its special properties, the enzymes has considerable biotechnological potential.